An industrial line scan low-distortion large target lens

Abstract

The application relates to an industrial line scanning low-distortion large target surface lens, an optical system of the lens comprising a front lens group A, a diaphragm, a rear lens group B and a rear lens group C, the front lens group A comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, the third lens and the fourth lens being tightly combined to form a first cemented lens group, the fifth lens and the sixth lens being tightly combined to form a second cemented lens group; the rear lens group B comprising a seventh lens, an eighth lens and a ninth lens, the seventh lens and the eighth lens being tightly combined to form a third cemented lens group, the rear lens group C comprising a tenth lens, an eleventh lens and a twelfth lens, the tenth lens and the eleventh lens being tightly combined to form a fourth cemented lens group, the focal length of the optical system being f, the focal length of the first cemented lens group being f1, the focal length of the second cemented lens group being f2, the focal length of the third cemented lens group being f3, and the focal length of the fourth cemented lens group being f4, the relationship being 1<|f1 / f|<2, 0.5<|f2 / f|<1, 10<|f3 / f|<16 and 1<|f4 / f|<2.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical lens, in particular to a kind of for industrial line scanning low distortion large target surface lens. BACKGROUND

[0002] Machine vision is to replace human eye to measure and judge with machine.Currently, line scanning lens is an important component of many machine vision systems.In electronic manufacturing, liquid crystal screen size measurement, circuit board pin detection and other precision detection applications, line scanning lens is often used to cooperate with line array camera to obtain image, and through clear and accurate lens, real image is obtained, which is the basis for subsequent image analysis and processing.Currently, the performance of line scanning lens on market in imaging clarity and distortion rate is not satisfactory, which cannot meet the application requirements of high resolution, large target surface and low distortion in the changing times. SUMMARY

[0003] (I) Technical problem to be solved

[0004] In order to solve the above problems of prior art, the present application provides a kind of for industrial line scanning low distortion large target surface lens, with high resolution, large target surface, low distortion performance, meet the demand of high-end products.

[0005] (II) Technical scheme

[0006] In order to achieve the above purpose, the main technical scheme adopted by the present application includes: a kind of for industrial line scanning low distortion large target surface lens, the optical system of lens is sequentially arranged from front to back along the light incident direction and is composed of front lens group A, diaphragm, rear lens group B and rear lens group C, the front lens group A includes sequentially arranged from front to back along the light incident direction and is composed of first lens, second lens, third lens, fourth lens, fifth lens and sixth lens, the third lens and the fourth lens are tightly formed into first cemented lens group, and the fifth lens and the sixth lens are tightly formed into second cemented lens group;The front end surface of the first lens, the second lens, the third lens, the fifth lens is convex, and the rear end surface of the fourth lens and the sixth lens is concave;

[0007] The rear lens group B includes sequentially arranged from front to back along the light incident direction and is composed of seventh lens, eighth lens and ninth lens, the seventh lens and the eighth lens are tightly formed into third cemented lens group, the front end surface of the seventh lens is concave, the rear end surface of the eighth lens is convex, and at least one of the front end surface and the rear end surface of the ninth lens is convex;

[0008] The rear lens group C comprises a tenth lens, an eleventh lens and a twelfth lens arranged in sequence from front to rear along the light ray incident direction, the tenth lens and the eleventh lens form a fourth cemented lens group in close contact, the front end face of the tenth lens and the rear end face of the eleventh lens are both concave, and the rear end face of the twelfth lens is convex;

[0009] The first lens and the second lens have positive focal power, the third lens and the fourth lens, the fifth lens and the sixth lens are double cemented lenses having negative focal power, the seventh lens and the eighth lens are double cemented lenses having negative focal power, and the ninth lens has positive focal power;

[0010] The tenth lens and the eleventh lens are double cemented lenses having negative focal power, and the twelfth lens has positive focal power;

[0011] The focal length of the optical system is f, the focal length of the first cemented lens group is f1, the focal length of the second cemented lens group is f2, the focal length of the third cemented lens group is f3, and the focal length of the fourth cemented lens group is f4, and the relationship between the focal lengths is simultaneously satisfied: 1<|f1 / f|<2, 0.5<|f2 / f|<1, 10<|f3 / f|<16, and 1<|f4 / f|<2.

[0012] (Three) beneficial effects

[0013] The beneficial effects of the present application are: the F number of the lens structure based on the present application is 3.8, the maximum imaging surface is Φ62mm, the resolution can reach 100lp / mm, the maximum optical distortion of the full field of view is less than 0.026%, it has the performance of high resolution, large target surface and low distortion, meets the demand of high-end products, and the light aperture can also be flexibly adjusted by using the whole focusing mode. BRIEF DESCRIPTION OF DRAWINGS

[0014] Fig. 1 It is a structural schematic diagram of the present application;

[0015] Fig. 2 It is an optical path diagram of the optical system in the embodiment of the present application;

[0016] Fig. 3 It is a distortion curve diagram of the optical system in the embodiment of the present application;

[0017]

Explanation of reference signs

[0018] L1, first lens; L2, second lens; L3, third lens; L4, fourth lens; L5, fifth lens; L6, sixth lens; L7, seventh lens; L8, eighth lens; L9, ninth lens; L10, tenth lens; L11, eleventh lens; L12, twelfth lens;

[0019] U1, first cemented lens group; U2, second cemented lens group; U3, third cemented lens group; U4, fourth cemented lens group;

[0020] STO, diaphragm;

[0021] L, distance from the front vertex of the first lens to the rear vertex of the twelfth lens;

[0022] BFL, optical back focal length of the optical system. DETAILED DESCRIPTION

[0023] In order to better explain the present application, so as to be understood, the present application is described in detail below by specific embodiments in combination with the drawings.

[0024] Embodiment one

[0025] Please refer to Figs. 1 to 3 Fig. 1 shows a lens for industrial line scanning low distortion large target, the optical system of the lens is composed of front lens group A, diaphragm STO, rear lens group B and rear lens group C arranged in order from front to back along the light incident direction, the front lens group A includes first lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5 and sixth lens L6 arranged in order from front to back along the light incident direction, the third lens L3 and the fourth lens L4 are tightly formed into the first cemented lens group U1, and the fifth lens L5 and the sixth lens L6 are tightly formed into the second cemented lens group U2; the front end face of the first lens L1, the second lens L2, the third lens L3 and the fifth lens L5 is a convex surface, and the rear end face of the fourth lens L4 and the sixth lens L6 is a concave surface;

[0026] The rear lens group B includes seventh lens L7, eighth lens L8 and ninth lens L9 arranged in order from front to back along the light incident direction, the seventh lens L7 and the eighth lens L8 are tightly formed into the third cemented lens group U3, the front end face of the seventh lens L7 is a concave surface, the rear end face of the eighth lens L8 is a convex surface, and at least one of the front end face and the rear end face of the ninth lens L9 is a convex surface;

[0027] The rear lens group C includes tenth lens L10, eleventh lens L11 and twelfth lens L12 arranged in order from front to back along the light incident direction, the tenth lens L10 and the eleventh lens L11 are tightly formed into the fourth cemented lens group U4, the front end face of the tenth lens L10 and the rear end face of the eleventh lens L11 are concave surfaces, and the rear end face of the twelfth lens L12 is a convex surface;

[0028] The first lens L1, the second lens L2 have positive focal power, the third lens L3 and the fourth lens L4, the fifth lens L5 and the sixth lens L6 are double cemented lenses having negative focal power, the seventh lens L7 and the eighth lens L8 are double cemented lenses having negative focal power, the ninth lens L9 has positive focal power;

[0029] The tenth lens L10 and the eleventh lens L11 are double cemented lenses having negative focal power, the twelfth lens L12 has positive focal power;

[0030] The focal length of the optical system is f, the focal length of the first cemented lens group U1 is f1, the focal length of the second cemented lens group U2 is f2, the focal length of the third cemented lens group U3 is f3, the focal length of the fourth cemented lens group U4 is f4, and the relationship between the focal lengths is simultaneously satisfied: 1<|f1 / f|<2, 0.5<|f2 / f|<1, 10<|f3 / f|<16, 1<|f4 / f|<2.

[0031] Preferably, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, the eighth lens L8, the ninth lens L9, the tenth lens L10, the eleventh lens L11, and the twelfth lens L12 are all spherical mirrors.

[0032] Preferably, the first lens L1 has positive focal power.

[0033] Preferably, the third lens L3 in the first cemented lens group U1 has negative focal power, and the fourth lens L4 has positive focal power.

[0034] Preferably, the rear end face of the third lens L3 in the first cemented lens group U1 is concave, and the front end face of the fourth lens L4 is convex.

[0035] Preferably, the fifth lens L5 has positive focal power, and the sixth lens L6 has negative focal power.

[0036] Preferably, the rear end face of the fifth lens L5 in the second cemented lens group U2 is concave, and the front end face of the sixth lens L6 is convex.

[0037] Preferably, the seventh lens L7 in the third cemented lens group U3 has negative focal power, and the eighth lens L8 has positive focal power.

[0038] Preferably, the rear end face of the seventh lens L7 in the third cemented lens group U3 is concave, and the front end face of the eighth lens L8 is convex.

[0039] Preferably, the tenth lens L10 in the fourth cemented lens group U4 has positive refractive power, and the eleventh lens L11 has negative refractive power.

[0040] Preferably, the back end surface of the tenth lens L10 in the fourth cemented lens group U4 is a convex surface, and the front end surface of the eleventh lens L11 is a concave surface.

[0041] Preferably, the twelfth lens L12 has positive refractive power.

[0042] Preferably, the distance L from the front surface vertex of the first lens L1 to the back surface vertex of the twelfth lens L12 and the focal length f of the optical system satisfy the relationship: 0.5<|L / f|<1.

[0043] Preferably, the optical back track length BFL of the optical system and the focal length f of the optical system satisfy the relationship: 0.5<|BFL / f|<1.

[0044] The half image height y' of the optical system and the focal length f of the optical system satisfy the relationship: |y' / f|<0.5.

[0045] In the present example, the optical system data are as follows:

[0046]

[0047]

[0048] In this example, the focal length f of the optical system is 98 mm, the maximum aperture is F# = 3.8, the focal length f1 of the first cemented lens group U1 is -195.0 mm, the focal length f2 of the second cemented lens group U2 is -81.9 mm, the focal length f3 of the third cemented lens group U3 is 1447.2 mm, the focal length f4 of the fourth cemented lens group U4 is -121.4 mm, the distance L from the vertex of the front surface of the first lens L1 to the vertex of the rear surface of the twelfth lens L12 is 84.9 mm, the optical back focal length BFL is 74.2 mm, the half image height y' is 31.62 mm, the focal length fL1 of the first lens L1 is 146.3 mm, the focal length fL2 of the second lens L2 is 164.8 mm, the focal length fL3 of the third lens L3 is -91.9 mm, the focal length fL4 of the fourth lens L4 is 147.5 mm, the focal length fL5 of the fifth lens L5 is 78.5 mm, the focal length fL6 of the sixth lens L6 is -37.8 mm, the focal length fL7 of the seventh lens L7 is -60.0 mm, the focal length fL8 of the eighth lens L8 is 60.7 mm, the focal length fL9 of the ninth lens L9 is 87.1 mm, the focal length fL10 of the tenth lens L10 is 66.5 mm, the focal length fL11 of the eleventh lens L11 is -43.3 mm, and the focal length fL12 of the twelfth lens L12 is 102.2 mm.

[0049] Each of the following relationships: |f1 / f| = 1.99; |f2 / f| = 0.83; |f3 / f| = 11.69; |f4 / f| = 1.24; |L / f| = 0.87; |BFL / f| = 0.76; |y' / f| = 0.33.

[0050] The following relationships are satisfied: 1 < |f1 / f| < 2; 0.5 < |f2 / f| < 1; 10 < |f3 / f| < 16; 1 < |f4 / f| < 2; 0.5 < |L / f| < 1; 0.5 < |BFL / f| < 1; |y' / f| < 0.55.

[0051] The embodiment of the present application is tested to obtain Fig. 2 and Fig. 3 , Fig. 2 The optical path diagram of the optical system in the embodiment of the present application is shown in Fig. 3 The optical distortion curve diagram of the present embodiment is shown in Fig. 3 It can be seen that the maximum optical distortion in the full field of view range is less than 0.026%.

[0052] The optical system of the line scanning machine vision lens with a focal length of 98mm is realized, the F number of the image side is 3.8, the maximum imaging surface is Φ62mm, the resolution can reach 100lp / mm, the maximum optical distortion of the full field of view is less than 0.026%, the performance of high resolution, large target surface and low distortion is achieved, the demand of high-end products is met, the whole focusing mode is adopted, and the light aperture can be flexibly adjusted.

[0053] The above only describes the embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent transformation or direct or indirect application in the related technical field by using the content of the specification and drawings of the present application is also included in the patent protection scope of the present application.

Claims

1. An industrial line scan low-distortion large target lens, the optical system of the lens is composed of a front lens group A, a diaphragm, a rear lens group B and a rear lens group C arranged in order from front to back along the light incident direction, characterized in that, The front lens group A includes, in order from front to back along the light ray incident direction, a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, the third lens and the fourth lens form a first cemented lens group in close contact, the fifth lens and the sixth lens form a second cemented lens group in close contact; the front end surface of the first lens, the second lens, the third lens, the fifth lens is a convex surface, the rear end surface of the fourth lens and the sixth lens is a concave surface; The rear lens group B includes, in order from front to back along the light ray incident direction, a seventh lens, an eighth lens and a ninth lens, the seventh lens and the eighth lens form a third cemented lens group in close contact, the front end surface of the seventh lens is a concave surface, the rear end surface of the eighth lens is a convex surface, at least one of the front end surface and the rear end surface of the ninth lens is a convex surface; The rear lens group C includes, in order from front to back along the light ray incident direction, a tenth lens, an eleventh lens and a twelfth lens, the tenth lens and the eleventh lens form a fourth cemented lens group in close contact, the front end surface of the tenth lens and the rear end surface of the eleventh lens are concave surfaces, the rear end surface of the twelfth lens is a convex surface; The first lens and the second lens have positive focal power, the third lens and the fourth lens, the fifth lens and the sixth lens are double cemented lenses with negative focal power, the seventh lens and the eighth lens are double cemented lenses with negative focal power, and the ninth lens has positive focal power; The tenth lens and the eleventh lens are double cemented lenses with negative focal power, and the twelfth lens has positive focal power; The focal length of the optical system is f, the focal length of the first cemented lens group is f1, the focal length of the second cemented lens group is f2, the focal length of the third cemented lens group is f3, and the focal length of the fourth cemented lens group is f4, and the relationship between the focal lengths is simultaneously satisfied: 1<|f1 / f|<2, 0.5<|f2 / f|<1, 10<|f3 / f|<16, 1<|f4 / f|<2.

2. The low-distortion large target industrial line-scan lens of claim 1, wherein, The third lens in the first cemented lens group has negative focal power, and the fourth lens has positive focal power.

3. The low-distortion large target industrial line-scan lens of claim 1, wherein, The fifth lens has positive focal power, and the sixth lens has negative focal power.

4. The low-distortion large target industrial line-scan lens of claim 1, wherein, The seventh lens in the third cemented lens group has negative focal power, and the eighth lens has positive focal power.

5. The low-distortion large target industrial line-scan lens of claim 1, wherein, The tenth lens in the fourth cemented lens group has positive focal power, and the eleventh lens has negative focal power.

6. The low distortion large target industrial line scan lens of claim 1, wherein: The distance L from the front surface vertex of the first lens to the rear surface vertex of the twelfth lens satisfies the relationship: 0.5<|L / f|<1.

7. The low-distortion large target industrial line-scan lens of claim 1 or 6, wherein: The optical back aperture BFL of the optical system satisfies the relationship: 0.5<|BFL / f|<1.

8. The industrial line scan low distortion large target lens according to claim 1, wherein the half image height y' of the optical system satisfies the relationship: |y' / f|<0.5.

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